/* Example 4.2
 Annoying siren
 CC by-sa v3.0
 http://tronixstuff.wordpress.com */

void setup()
{
  pinMode(8, OUTPUT); // speker on pin 8
}

int del = 250; // for tone length
int lowrange = 2000; // the lowest frequency value to use
int highrange = 4000; //  the highest...

void loop()
{
  // increasing tone
  for (int a = lowrange; a<=highrange; a++)
  {
    tone (8, a, del);
  }
  // decreasing tone
  for (int a = highrange; a>=lowrange; a--)
  {
    tone (8, a, del);
  }
}


